Enter an amount, an assumed average annual inflation rate, and a number of years. See either what your money will effectively be worth (buying power) or what today's price tag will cost in the future.
How this inflation calculator works
First, what this is not: a historical CPI lookup. It won't tell you what a 1980 dollar equals today, because it doesn't contain any price data at all. Instead it's a fixed-rate projection — you pick one average annual inflation rate, and it compounds that rate forward for as many years as you choose. That's exactly what you want for planning: nobody knows future inflation, so you assume a rate (the US long-run average is about 3.2% a year) and see where it leads. Run it at a couple of different rates to get a range instead of a single falsely precise answer.
The formula
Future buying power = Amount ÷ (1 + r)t
Future cost = Amount × (1 + r)t
r is the assumed average annual inflation rate as a decimal (3% = 0.03) and t is the number of years. Inflation compounds just like interest — it's the same exponential curve working against you instead of for you.
Worked example
Take $100 at 3% average inflation over 20 years. (1.03)20 ≈ 1.8061.
Buying power: $100 ÷ 1.8061 = $55.37 — in 20 years, your $100 bill buys what $55.37 buys today.
Future cost: $100 × 1.8061 = $180.61 — what today's $100 grocery run will cost then.
Two questions, one curve
The two modes are the same math read in opposite directions, and people constantly mix them up. Buying power holds the dollars fixed and shrinks what they buy — use it to judge cash sitting in a low-interest account. Future cost holds the goods fixed and inflates the price tag — use it to set savings targets ("college will cost X in 15 years"). A useful mental shortcut is the rule of 72: divide 72 by the inflation rate to get the doubling time for prices. At 3%, prices double — and idle cash halves — roughly every 24 years, which is why "safe" cash is anything but safe over long horizons.
Frequently asked questions
Does this calculator use real historical inflation data?
No — it's a fixed-rate projection, not a CPI lookup. You choose one average annual rate and it compounds that rate forward. That makes it ideal for planning ('what if inflation averages 3%?') but it won't tell you what a 1975 dollar is worth today; historical questions need actual CPI data.
What inflation rate should I use?
The long-run US average is about 3.2% per year, which is why 3% is a common planning default. Recent decades ran closer to 2%–2.5%, while 2021–2022 spiked far above that. For long-horizon planning, running the calculator at 2%, 3%, and 4% gives you a realistic range rather than one false-precision answer.
What's the difference between the two modes?
Future buying power answers 'what will my $1,000 really be worth?' — it divides by (1+r)^t, so the number shrinks. Required future amount answers 'what will something costing $1,000 today cost later?' — it multiplies by (1+r)^t, so the number grows. Same math, opposite directions.
What is the formula for inflation-adjusted value?
Future buying power = Amount ÷ (1 + r)^t, and future cost = Amount × (1 + r)^t, where r is the annual inflation rate as a decimal and t is the number of years. At 3% for 20 years, $100 of buying power shrinks to $55.37, while a $100 price tag grows to $180.61.
Why does inflation matter for my savings?
Cash that earns less than inflation is quietly losing value every year. At 3% inflation, money sitting idle loses roughly half its buying power in about 24 years (the rule of 72: 72 ÷ 3 = 24). That's the core argument for investing long-term savings rather than holding them entirely in cash.